Weichai America Corp.
107
b)
Low charging voltage
Failure2: Low charging voltage
Vehicle fault
Fault testing
Troubleshooting
Battery is often
undercharged,
charging voltage
is
low
and
voltage decreases
obviously
with
open load
Check if alternator
output power and
vehicle electrical
appliance are properly
matched.
Test the voltage at alternator terminal B+ and which should be (27.8~28.4)
V. If the voltage is normal, it indicates voltmeter or sampling point is
failure, and require to be repaired or replaced.
a. Check voltmeter for
damage
b. Check alternator
speed.
a. No-load speed of alternator is recommended to be more than 1,600rpm.
b. The speed should be ≥2,000rpm or voltage be approximately 27V when
alternator operates with high power load like A/C.
c. Check the quality
and tension of
alternator and related
transmission belt.
a. Check the qualities of alternator and related transmission belt, and if the
belt is coking, lack of teeth, broken, deformed or if it have fall into pulley
groove bottom, replace it timely.
b. Retighten alternator and related belts.
Notice: If the system is drove by dual belt, then two belts shall be replaced
simultaneously.
d. Check alternator
pulley
Tighten if it is loose.
e. Check whether the
lead is used properly,
and test the voltages at
alternator and battery
terminals.
a. In case of voltage difference more than 1V (big voltage drop due to thin
wire) under heavy load working condition, please replace the wire.
If the current is less than or equal to 35A, S should be greater than or
equal to 6mm
2
;
If the current is less than or equal to 70A, S should be more than or equal
to 12mm
2
;
If the current is less than or equal to 100A, S should be more than or equal
to 20mm
2
;
If the current is less than or equal to 150A, S should be more than or equal
to 25mm
2
.
b. If the lead wire or connector become very hot under heavy load working
condition, replace the lead or connector.
f. Inspect whether
charging system wire
is connected to bolt
firmly, and whether it
is oxidized, virtual
connected and
overheated.
a. Polish the lug plate with its surface oxidized and surface of ground bolt
housing for subsequent reinstallation.
b. Retighten the loose nut and lug plate, and reinsert connector into place.
Notice: Check if the reinstalled or re-tightened parts are still very hot after
engine runs with heavy load for (3~5) min.
g. Test the phase
output voltage of
alternator (which
When the phase output voltage (W/R/AC) is greatly different from normal
output voltage valve, alternator rectifier bridge or stator has failed, and
reconditioning or replacement should be considered.
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